In an ad-hoc network, node apparatuses spontaneously form a network. Since communication is spontaneously performed, a user does not set a communication route where appropriate and communication terminals for communication management, such as servers and routers, and infrastructures are not used.
Examples of a node apparatus which is connected to the ad-hoc network include a gateway apparatus (hereinafter referred to as a “GW” where appropriate). The gateway apparatus has a function of communicating with a server. As a related art, a technique of performing switching of a gateway function in an ad-hoc network system has been proposed (refer to Japanese Patent Laid-Open No. 2008-193318, for example).